Communication system



March 15, V M BUGGE ET AL 2,111,138

COMMUNICATION SYSTEM Filed Sept. 28, 1955 2 Sheets-Sheet 2 x\ z mugFIG.3.

INVENTORQ ATTORNEY Patented Mar. 15, 1938 UNITED STATES PATENT OFFICECOIVEMUNICATION SYSTEM Application September 28, 1935, Serial No. 42,641

7 Claims.

This invention relates to communication systems and'more particularly toprinting telegraph systems of the non-synchronous type.

The principle of the system employed in the present invention instead ofdepending on the synchronous operation of the transmitting and receivingunits operates on the basis of the transmission of signals ofpredetermined current values to which the receiving unit will give a 10definite and different response to each signal. A system of this type isfully disclosed and described in a copending application, Serial No.737,013, filed July 26, 1934.

The present invention is in the form of an improvement of the systemdescribed in the aforesaid application. Briefly and broadly, the systemin said application comprises a transmitting unit to initiate charactersignals consisting of code combinations of impulses having differentialcurrent values and polarity. The receiving unit includes relaydevicessensitive to said impulse characteristics to control the selection ofdifferent circuits, for example, a galvanometer relay of the DArsonoaltype may be used to respond to the different current values employed andthe polarity of the impulses, so that the relay brush or armature ispositioned to engage one of a plurality of contacts in accordance withthe characteristics of the character signal. In addition 0 thereto,another relay device may be used to be responsive only to the number ofimpulses included in the code combinations, in turn, controllinga devicesuch as a relay to be operated step by step such as the well known typeof step- 35 ping relay.

A pluraiity of circuits are associated with the galvanometer relaycontacts and with the contacts of the stepping relay and are arranged sothat upon the respective positioning of the galva- 40 nometer relayandthe stepping relay, a single circuit corresponding to the charactersignal is selected to be energized effecting registration of theselected character. I

An object of the present invention is to provide 45 for a morepositive-system when adverse line and operating conditions areencountered thereby providing a system capable of faster rates oftransmission of the character signals.

Another object of the present invention "is to 50 provide for increasingthe margin of operation of the relay device responsive to the impulsecharacteristics. In the aforesaid application, the brush or armature ofthe galvanometer relay was provided to be damped to the extent that the55' associated contacts were not engaged during transmission of theshort impulses and positioned only upon reception of the longer impulse.The circuit arrangement is such that battery is applied to the brush orarmature at all times. In the present invention, a similar device may beused without the extreme damping so as to permit the brush or armatureto travel over the associated contacts upon reception of the shorterimpulses and yet not effect improper or faulty selection andregistration of the characters.

The battery is connected to the said brush only during the timedinterval the long impulse is re ceived.

Still another object of the present invention is to compensate for thetime lag of the various relay control circuits, for example, thestepping relay circuits.

Still another object of the present invention is to provide forrestoring the conditioned and operated circuits to normal under controlof the recording unit, in contradistinction to, a predetermined timeddelay circuit independent of the receiving unit as described in theaforesaid application.

Various other objects and advantages of the invention will be obviousfrom the following particular description of one form of mechanismembodying the invention or from an inspection of the accompanyingdrawings; and the invention also constitutes certain new and usefulfeatures of construction and combination of parts hereinafter set forthand claimed.

In the drawings:

Fig. 1 is a schematic diagram showing one form of the connections of theimpulse transmitter.

Fig. 2 is a preferred form of the code used in conjunction with thepresent invention.

Fig. 3 is a schematic diagram showing, one form of circuit arrangementof the receiving system.

Referring now to Fig. 1, a plurality of pulse wheels or disks M areshown with a combination of conducting segments 16 thereon. Thearrangement and number of conducting segments for each disk correspondsto the code shown in Fig. 2, for example, the character S, the code ofwhich is current value I, positive polarity and four impulses, namely,three short impulses and one long impulse. Therefore, on the disk II forthe character S, four conducting. segments I6 are disposed thereon sothat the three short pulses of current are conducted before the longsegment engages the contacts H to transmit the long impulse of itscorresponding current value.

It is to be noted that for characters represented by a plurality ofimpulses the last impulse is always a long impulse the significance ofwhich will be understood as the description progresses. Each disktherefore has disposed thereupon the number of segments to correspond tothe number of impulses in its particular code. It is sufilcient tomention that upon depression of a character key of the typewriter (notshown) its corresponding disk i4 is released to complete one revolution,thereby conducting the proper increment of current value, polarity andthe number of impulses representing the character, to the connected linenetwork. A further description of the transmitting system may be had byreferring to the said prior application in which the transmittingtypewriter and mechanism for releasing the pulse wheels is shown andcompletely described. Since this mechanism forms no part of theinvention, it is deemed unnecessary to repeat such description.

With reference now to Fig. 3, the code combination of impulsesconsisting of predetermined characteristics are received over the lineassociated with the galvanometer relay 20 and line relay 2 I. Thegalvanometer relay 20 is shown to comprise an energizing coil 22connected directly across the line and adapted to be energized inaccordance with the various current strengths and polarity impressedthereupon to control the positioning of the armature 23 with respect tothe associated contacts 24. It is to be noted that there are eightcontacts 24, four contacts corresponding to the four increment currentvalues of positive polarity and four contacts for the four negativecurrent values. Therefore, upon receipt of the character impulses,either the short or long impulses, the armature 23 is positioned toengage the proper contact 24 in accordance with the character signaltransmitted.

To continue with the example, for character "5, the armature 23 ispositioned to contact 24'l of the positive group of contacts, for it isremembered that the code combination thereof is four impulses of thefirst current value and positive polarity.

Permitting the armature 23 to be responsive to both the short and longimpulses and thereby to be positioned engaging the correspondingcontacts 24 accordingly, it is obvious that the instrument needs noprecise damping features, resulting therefore in the possibility ofutilizing a less expensive selecting instrument, thus enhancing thepractical value of the system.

The relay device 2| also associated with the line is designed to beresponsive only to the number of impulses included in the codecombinations and transmitted accordingly. To assure accurate operationof the system the relay 2| should be a sensitive and fast operatingrelay, one type which may be provided therefore is a galvanometer relaysimilar to relay 20, however, a single contact 25, normally open, asshown, is all that is required. In addition thereto to provide foruni-directional operation a bridge rectifier unit 26 is interposedbetween the line and relay device 2|.

Connected to armature 21 of relay 2| by conductor 28 is the operatingcoil 29 of stepping relay 30, which is of a type well known and requiresno further description, and also fully described in the aforesaidapplication. It is sufficient to mention that for each impulse received,that is, every time the relay 2| is energized to close the associatedcontact 25, grounded battery 3| through normally closed contact 3811 isconnected to the coil 29 operating the stepping relay 3!], therebycausing the stepper brush arm 32 to he stepped ahead to the adjacentcontact 33.

Release coil 34 associated with the relay 30 controls the resetting ofcontact arm 32 to the normal position as indicated in the drawings, uponthe e nergization thereof.

Relay 35 is also connected to armature 21 and is designed to be a slowoperating relay. It was mentioned that relay 2| is operated upon receiptof all impulses closing the contact 25, however, the timed interval thecontact 25 is closed by the shorter impulses is not sufllcient to permitgrounded battery 3| to operate relay 35. It is only the longer impulseswhich energize the relay 2| closing the contact 25 to connect groundedbattery 3| to relay 35 for a timed period sufficient to energize thesaid relay.

It is obvious that the length of time the contacts 25 are closed doesnot effect the cycle of operation of the stepper relay 30, in that thestepper arm 32 is advanced upon the receipt of each impulse, either ashort or long impulse.

Energization of relay 35 operates the associated contacts 36 connectinggrounded battery 31 through the normally closed contact 38, conductor39, to relay 48, energizing the said relay, and establishing a lockingcircuit for relay 40 through the contacts 4| now closed. Groundedbattery 31 is also connected to the armature 23 of the galvanometerrelay 20 through the now closed contact 42.

It was mentioned hereinbefore that the armature of relay 20 could beundamped so as to engage the associated contacts 24 during its traveldue to the receipt of the character pulses. It was shown that battery isnot connected to the said armature until the receipt of the longimpulse, and for this reason, it is not possible to energize any of theassociated selector relays 43 to 5|) until the long impulse is receivedand in this manner cause a registration of an unwanted character.

Energization of any one of the selector relays 43 to 50 establishes alocking circuit for the corresponding relay through the associatedcontacts 5| to 58 as follows: from grounded battery 31 through normallyclosed contact 38, conductors 39 and 59, the particular associated andcorresponding contact of the said contacts 5| to 58 and the saidparticular selector relay of the group of relays 43 to 50 to ground 80.Operation of the particular selector relay permits a circuit to beconditioned through the now closed and associated contact of the groupof contacts 6| to 68 to energize the associated group control relay ofthe group of relays 69 to 16, as follows: grounded battery 31, throughnormally closed contact 38,

conductor 39, now closed contact 36, and common conductor 11 to energizethe particular group control relay thereby closing the associatedcontacts a to d.

It is obvious from the description thus far, that the'group controlrelays can only be operated when and only when the long impulse isreceived. The said impulse controls the connection of battery toarmature 23 of relay 20 and also the connection of battery throughcontact 36 to the group control relays. From the above it is seen how aparticular group control relay is selected in accordance with theimpulse characteristics due to the positioning of armature 23.

Operation of a group control relay selects from the total number ofcircuits associated with the group control relays, four predeterminedcircuits associated with the a to d contacts. Selection of a singlecircuit from the group of said predetermined circuits to correspond tothe received character signal is effected by the stopping relay 38.

The arm 32 is positioned to engage one of the four contacts 33 inaccordance with the number of impulses included in the code combinationof the transmitted character signal. Grounded battery 3| is theneffective to energize the selected circuit due to the completion of thesaid circuit through one of the stepper contacts 33, brush arm 32,normally closed contacts'IBa to ground 18.

Included in each one of the circuits associated with the group controlrelay contacts a to d is a solenoid 88, the energization of which iseffective to depress a character key of a suitable recorder, such as atypewriter or punch to register the character in accordance with thetransmission of the signals. One preferred type of recording device isfully disclosed and described in the aforementioned application in whichthe solenoid 38 corresponds to the said solenoid 80 in the presentinvention, and therefore requires no further discussion.

Upon depression or operation of a selected character key, contacts 8|are adapted to be operated. Specific mechanism for this provision is notshown since it is old and well known in the art; one method, which hasbeen used heretofore, is to provide a common bar beneath the key bars ofthe recorder and arranged so that the depression of the character keyslowers the common bar which in turn causes the common contacts to beclosed.

Operation of the contacts 8| connects grounded battery 31 to relay 82,coil 34 of the stepper relay 30 and relay 83 operating the said relaysto restore all the energized circuits in the receiving system to normalcondition as shown in the drawmgs.

Operation of relay 82 causes the contacts 38 and 38a to be openeddisconnecting battery 3'! from the operated selector relay of the groupof relays 43 to 50 thereby opening the locking circuit established, alsodisconnects battery from the armature 23 of relay 26 and opens thelocking circuit of relay 40, and too, opens the circuit to the groupcontrol relays, deenergizlng the particular operated relay, in turnopening the associated contacts a to d and thereby disconnecting battery3| from the solenoid circuits.

Energization of release coil 34 of relay 30 returns the stepper brusharm 32 to the normal position as indicated in Fig. 3, that is to aposition so as to engage the unconnected contact 33. Operation of relay83 opens the normally closed contacts 18 and 18a disconnecting groundfrom the brush arm 32 and coil- 28 of relay 30 thereby assuring that nofaulty operations of the recording unit on the stepper relay may bemade;

The operation of the receiving circuit just de scribed will now beexplained for the reception of a particular character signal, namely,for the character S"; It was mentioned hereinbefore that the ccdecombination of said character is four impulses of the first currentvalue of positive polarity, therefore upon receipt thereof, the armature23 of the galvanometer relay 20 is positioned to engage the contact 24-|of the positive group. However, so long as battery 31 isdisconnectedfrom the armature 23, the final selection of the circuitsand energization thereof corresponding to the character signal cannot bemade.

Reception of the four impulses causes relay 2| to be operated four timessuccessively permitting grounded battery 3| to energize the coil 29 ofstepping relay 30 accordingly and thereby positioning the brush arm 32to engage contact 334, the engagement of said contact is maintaineduntil the brush arm 32 is released due to the energization of releasecoil 34.

In accordance with the description set forth, relay 35 remainsinoperative during the reception of the three short impulses of thecode, however, the long impulse energizes relay 2| for a timed intervalsuflicient for battery 3| to energize relay 35 and operate theassociated contacts 36. Battery 31 is now connected to relay 48 tooperate said relay, establishing a locking circuit therefor through theassociated contact 48.

During the timed interval of the reception of the long impulse armature23 is positioned to engage contact 24-! of the-positive group, so thatbattery 31 is now connected through contact 42 (now closed), armature23, contact 24| of the positive group, selector relay 46 to ground,operating said selector relay to close the associated contacts 54 and64. A locking circuit for relay 46 is established through contact 54,and through contact 64, battery 31 is connected through contact 36 andconductor 11 to energize group control relay 12 operating theassociatedv a to (1 contacts. The solenoid circuits for characters S, Z,A, and SP are connected to the said a to d contacts, however, only the Scircuit becomes operative due to the said positioning of brush arm 32 ofrelay 30 so as to engage contact 334 thereby permitting battery 3| toenergize the solenoid 80 to depress a character key corresponding to thecharacter 8".

Operation of the said character key closes the normally open contacts 8icausing relays 82 and 83 and release coil 34 of relay 30 to beenergized. Due to the energization of release coil 34 brush arm 32 isreset to its normal position to engage the unconnected contact33;energization of relay 83 opens the normally closed contacts 18 and18a to disconnect ground 19 from the associated circuits; andenergization of relay 82 opens the nor mally closed contacts 38 and 38adisconnecting the batteries 3? and 3| respectively, from the associatedcircuits to deenergize relays 35, 40, 46, and 12 thereby restoring theconditioned circuits to normal. Upon registration of the character S",contacts 8! are opened de-energizing relays 82 and 83 and release coil34 to permit further conditioning and operation of the charactersolenoid circuits in accordance with the subsequent transmission of thecharacter signals.

While there has been shown and described and pointed out the fundamentalnovel features of the invention as applied to a single modification, itwill be understood that'various omissions and substitutions and changesin the form and details of the device illustrated and in its operationmay be made by those skilled in the art without departing from thespirit of the invention. It is the intention therefore to be limitedonly as indicated by the scope of the following claims.

What is claimed is as follows:

1. A communication system of the character described comprising meansfor transmitting character signals consisting of code combinations ofimpulses having different current values and polarity, selectivelyoperable means responsive to the currentvalues and polarity of thesignals, a device responsive only to the different number of impulsesincluded in the signal code, a plurality of circuits associated with thesaid selectively operable means and said device, a power supply normallydisconnected from the said. selectively operable means, and means uponreception of a predetermined impulse to connect the said power supply tosaid selectively operable means to effect a selection of a singlecircuit from the said plurality of circuits in accordance with thesignal transmitted.

2. A communication system of the character described comprising meansfor transmitting character signals consisting of code combinations ofimpulses having different current values and polarity, selectivelyoperable means responsive to the current values and polarity of thesignals, said operable means comprising relay means adapted to bepositioned to engage oneof a plurality of contact segments in accordancewith. the current values and polarity of the impulses, a deviceresponsive only to the difierent number of impulses included in thesignal code, a plurality of circuits associated with the saidselectively operable means and said device, a power supply normallydisconnected from the said selectively operable means, and means uponreception of a predetermined impulse to connect the said power supply tosaid selectively operable means to effect a selection of a singlecircuit from the said plurality of circuits in accordance with thesignal transmitted.

3. A communication systemof the character described comprising aplurality of circuits corresponding to predetermined signals, means fortransmitting character signals consisting of code combinations ofimpulses of difierent current values and polarity, means responsivesolely to said current values and polarity and means responsive only tothe diflerent number of impulses to select from the plurality ofcircuits those which correspond to thetransmitted character signals,means to energize said selected circuits, recording means operated bythe said selected circuits and means directly controlled by therecording means to deenergize the said selected circuits upon operationthereof.

4. A communication system of the character described comprising meansfor transmitting character signals consisting of code combinations ofimpulses having different current values and polarity, a plurality ofcircuits corresponding to the different characters, a relay deviceresponsive to the different current values and polarity of the signalsand means responsive to the different number of impulses of saidcombinations to select a circuit from the said plurality of circuits,means to energize the said selected circuii 'an indicating deviceoperated by the said selected circuit, and means under the directcontrol or the indicating device to deenergize thesaid selected circuitupon operation thereof.

5. A communication system of the character described comprising means totransmit character signals comprising code combinations of impulseshaving different current values and polarity, a plurality of circuits,means responsive only to said current values and polarity of theimpulses and means responsive only to the diiferent numbers of impulsesof said combinations to eifect the selection of a circuit from saidplurality of circuits and means including control circuits to beconditioned during the transmission of the impulses to maintain theselection of said particular circuit upon dicontinuance of thetransmission of the character signal.

6. A communication system of the character described comprising means totransmit character signals comprising code combinations of impulseshaving difierent current values and polarity, a plurality of circuits, arelay device responsive to the current values and polarity of theimpulses and means responsive to the different number of impulses ofsaid combinations to effect the selection of a particular circuit fromsaid plurality of circuits in accordance with the character signaltransmitted, means including control circuits to be conditioned duringthe transmission of the impulses to maintain the selection of the saidparticular circuit upon discontinuance of transmission of the charactersignal, an indicating device operated by said selected circuit, andmeans to restore the conditioned circuits to normal condition uponoperation of said receiving device.

7. A communication system of the character described comprising means totransmit character signals comprising code combinations of impulseshaving difierent current values and polarity, a plurality of circuits, arelay device responsive to the current values and polarity of theimpulses and means responsive to the diiferent number of impulses ofsaid combinations to effect selection of a particular circuit from saidplurality of circuits in accordance with the character signaltransmitted, means including control circuits to be conditioned duringthe transmission of the impulses to maintain the selection of the saidparticular circuit upon discontinuance of transmission of the charactersignal, an indicating device operated by said selected circuit, andmeans operated directly by said indicating device to restore theconditioned circuits to normal condition upon operation of saidindicating device.

\ VERNON M. BUGGE. JOHN D. JOHNSTON.

